View Full Version : gas mileage ?



ck253
08-08-2009, 07:54 PM
have 454 mpi in my 98 253 with a 23 p mirage prop put about a hour on the boat today just cruising around mostly about 35 mph and went through about 100 bux in gas is that right? I was thinking about putting a 25 or 26 4 blade on it. I am thinking that will help th fuel mileage alittle.

ck253
08-09-2009, 03:28 PM
its close to 5000 rpms at wot. that why I was thinking alittle more prop. at about 32-35 its at about 3300 rpms

PURPLE HORNET
08-09-2009, 04:00 PM
I would not go any higher then a 24p bravo 1 4 blade. If you have a stock 454 in that 253 a 26p will be to much prop. That 23 sounds about right for your set up

How much are you paying for a gallon of gas

noyzee
08-09-2009, 05:05 PM
strange, my boat has a great cruz speed. at 3400 rpm im at about 42 mph 3600-3800 in just about 50 mph. top speed sucks tho at about 60-62 depending on the load.

ck253
08-09-2009, 07:11 PM
paying about 3.05 a gallon.

noyzee- what kind of boat do you have and what prop is on it?

baja bailey
08-09-2009, 07:34 PM
Looks like you used about 33 gallons, seems a little much for an hour of just cruising ?

ck253
08-09-2009, 07:45 PM
ya thats what i thought!

RHM253
08-09-2009, 07:55 PM
I have a 95 253 509 procharged. If I cruise at 3000-3400
rpms turning Bravo 1 34p. I'll use about 11 gallons an hr. If I run hard I seem to use 11 gallons a minute!

ck253
08-10-2009, 06:29 AM
so i am thinking either a 24 bravo 1 or a 25 3 blade.

PURPLE HORNET
08-10-2009, 10:15 AM
so i am thinking either a 24 bravo 1 or a 25 3 blade.

A 25p will be to much also if you are stock in your boat. A 24p bravo,, I really think will be pushing it to much.

You say you have a 23 turnning a hair under 5000 rpms maybe 22p bravo 1 4 blade would be a better choice the more I think about it.

What HP is your engine

noyzee
08-10-2009, 12:49 PM
i run a lab 24 b1 prop

my cruz speed is about the same as it was with my 22p b 1 but my boat was hitting the rev limiter with the 22.
now with the 24 labbed im about 4700 rpm on the tach.

i tried a 3 blade 23 and my cruz speed dropped into the 30's like 35-37, i couldnt trim, and i lost 3 mph on top end!!

i then tried a labbed 23 and hit the rev limiter

ck253
08-10-2009, 04:41 PM
i run a lab 24 b1 prop

my cruz speed is about the same as it was with my 22p b 1 but my boat was hitting the rev limiter with the 22.
now with the 24 labbed im about 4700 rpm on the tach.

i tried a 3 blade 23 and my cruz speed dropped into the 30's like 35-37, i couldnt trim, and i lost 3 mph on top end!!

i then tried a labbed 23 and hit the rev limiter



what speed do you cruise at and what is your top end?

My motor is rated at 385 hp. Its the 454 efi. I think my top end is only in the high 50's right now. and i cruise at 32-34 at 3200 rpms. I am looking for more top end.

noyzee
08-13-2009, 10:59 AM
i cruz at around 3400-3600 rpm and my speed is around 41-44mph depending on how much i can trim (im on the ocean so its always a little bumpy) top end on my boat is between 60-62.X depending on load and conditions

my motor is rated at 375

ck253
08-13-2009, 12:17 PM
i take it you have the same boat as i do?

Bigsbetter
08-13-2009, 06:39 PM
I have a 1988 251 Convincor with a Stock 330 horse 454 with a Wieand 177 Supercharger. The boat is honestly more fuel efficient now than before the supercharger!...at cruise speeds. Last weekend the tank was almost empty, lets say it had 10-15 gallons in it, I put in 80bucks on land, that's about 30 gallons. We went down river 16 miles, did some runn'n around, maybe 5 miles, lots of WOT. Then headed up the Illinnoi river to Harden, maybe 20-25 miles, then back down, again some WOT but mostly cruising at 2500 rpm and going about 35 mph ...I think .After going back down the Illinoi river 25 miles we stopped and camped out and I was needing fuel. so lets add that up....I figure we drove 65-70 miles total on 45 gallons of gas. I had to put 20 bucks in it to get back 16 miles to my boat ramp. The 20 bucks only bought me 6.5 gallons and the gauge was in the same spot once I got to the ramp.

fireguy
08-13-2009, 11:04 PM
i take it you have the same boat as i do?

No, Noyzee has a 280ZT. So it is kinda apples and oranges.
I have a 96 253 with a 502 with a 24P B1 4 blade. I am running @ 4900 rpm WOT and my cruising RPM's depend on load. I try to stay @ 3200 when cruising, cuz from 3200 to 3800 I gotta fight the porpoising.

noyzee
08-14-2009, 08:39 AM
No, Noyzee has a 280ZT. So it is kinda apples and oranges.
I have a 96 253 with a 502 with a 24P B1 4 blade. I am running @ 4900 rpm WOT and my cruising RPM's depend on load. I try to stay @ 3200 when cruising, cuz from 3200 to 3800 I gotta fight the porpoising.

26. i wish it was a 28 but with more power. lol


it is apples to oranges, but ive also see a few boats work out bettet with the right prop. my old mans baja more like a conv hull (tru V style) picked up a good 3-4 mph cruz at 3400 rpm with a 4 blade over his 3 blade.
also, my buddys 25 outlaw with the right prop runs about the same cruz as me, he has allot more power but rpm to speed on our boats are very very close in the 3000-4000 rpm range.

best bet is to try to find some one with props to test

ck253
08-15-2009, 06:05 AM
24p 4 blade is the way to go !!!!

fireguy
08-15-2009, 05:01 PM
NOYZEE,
OOPS- thought you had a 280. Oh well, you still have a cool boat and I am still gonna try to copy your subwoofer mount this winter.

PURPLE HORNET
08-16-2009, 10:47 PM
I still feel a 24p will be a bit much for a 253 with a 385 horse engine more like a 22p 4 blade or stick with the 23p 3 blade thats on it

ck253
08-17-2009, 09:32 AM
borrowed a 24p from a friend. comes out of the hole a little slow but gained 3-4mph cruiseing and im well into the 60s top end and rpm range is right on the money when I get it trimed up!

noyzee
08-17-2009, 11:42 AM
fire guy. no problem. it works real well. i accually just dropped the boat off at my buddy again, he is going to see if i can add 2 6.5" jls out back so its allot louder on the beach. we'll see

ck, glad to hear that. i was going to tell you today that i was with a 253 this past weekend, he was running a rev 4 23p 4 blade with a lot of luck, but if the 24 worked. great even if your down 100-200 rpm, you can have it labbed and probably gain another 1 mph or so and get your rpm back. i bet the boat handles better as well

ck253
08-17-2009, 12:01 PM
it does hadle better and I plan i getting a labbed 24 so i am back .up in the range i had with the 23. I was talking with a friend of mine with a zt280 and he has a labbed 26 hydromotive and he loves it but he is running a 496.

noyzee
08-17-2009, 12:11 PM
it does hadle better and I plan i getting a labbed 24 so i am back .up in the range i had with the 23. I was talking with a friend of mine with a zt280 and he has a labbed 26 hydromotive and he loves it but he is running a 496.

thats what i would say. a labbed 24.
i have been talking with a few guys. (big dawgs compaired to us) 100+ mph boats, these guys are in the game. they have been there done that and they say the best prop for the money for basic boats like ours are labbed props right from merc. so if you looked into a merc labbed B1 24 p i bet you will be right on, and with the lab you should be back to faster planing.

ck253
08-17-2009, 02:21 PM
thanks for all the help guys

PURPLE HORNET
08-19-2009, 11:48 PM
I tried a factory labbed merc prop on my boat and it was horrible.